1. Field of the Invention
The present invention relates to a video processing method and apparatus. More particularly, the present invention relates to a video processing method and apparatus capable of performing a proper video process corresponding to multiple color systems.
2. Description of the Related Art
A video display apparatus, such as a television (TV), receives a video signal corresponding to an image transmitted from such sources as a digital TV broadcast and cable TV broadcast. A video display apparatus can also receive a video signal from various video devices such as a video cassette recorder (VCR) and a digital versatile disc (DVD) player. Further, video display apparatuses can process received video signals and display images accordingly.
A video processing apparatus includes a tuner to set a channel that a user wants to view. The tuner selects/receives a signal corresponding to a frequency assigned to the set channel, in other words the tuned channel. Also, the video processing apparatus includes a decoder which decodes signals corresponding to information about picture and sound, among others, from the received video signal. Since the signal selected and decoded by the video processing apparatus is based on international standards, the video processing apparatus is configured to process the signal on the basis of such international standards. The international standards include those standards such as national television system committee (NTSC), phase alternating line (PAL), Sequential couleur a memoire (SECAM), among others. Thus, the video processing apparatus is set to decode a signal according to at least one of the international standards.
For example, in the case of an NTSC-M standard, the field frequency is 59.72 Hz, the line frequency is 15.734266 KHz, and the color subcarrier frequency is 3.579545 MHz. Therefore, in a video processing apparatus receiving a signal based on the NTSC-M standard, when the received signal has a field frequency of 59.52 Hz, the decoding process is performed with the line frequency and the color subcarrier frequency established as preset 15.734266 KHz and 3.579545 MHz, respectively. Further, in the video processing apparatus receiving a signal based on a PAL-B/G/I standard, the decoding process is performed with a field frequency, line frequency and color subcarrier frequency established as 50 Hz, 15.625 KHz and 4.4336187 MHz, respectively. Thus, a conventional video processing apparatus identifies the field frequency of the received signal, then performs the decoding process on the basis of the preset line frequency and preset color subcarrier frequency corresponding to the identified field frequency.
Users often want a video processing apparatus to properly process signals based on a number of standards. For example, the video processing apparatus may be connected to a DVD player, a game system, or the like, and receive a signal therefrom and output a video signal and an audio signal. However, when the signal outputted from the DVD player, the game system, or the like, is not the same as the signal standard that the corresponding video processing apparatus is configured to accommodate, the video processing apparatus cannot provide proper video and audio signals.
For example, when a signal outputted from a game system is based on the NTSC-N standard, the signal has a field frequency of 50 Hz, but its line frequency and color subcarrier frequency are 15.625 KHz and 3.579545 MHz, respectively. Because the field frequency of the video processing apparatus receiving an NTSC-M standard signal is set to 60 Hz, the video processing apparatus cannot properly decode the signal outputted from such a video device. Meanwhile, in the case where the video processing apparatus is set to receive a PAL-B/G/I standard signal, the video processing apparatus determines that the input signal is based on the PAL-B/G/I standard because the input signal has a field frequency of 50 Hz. Thus, the video processing apparatus for the PAL-B/G/I standard tries to apply the decoding process to the input signal by regarding the corresponding line frequency and corresponding color subcarrier frequency as 15.625 KHz and 4.4336187 MHz, respectively. However, the real color subcarrier frequency of the input signal is not compatible with the preset color subcarrier frequency of the video processing apparatus. Thus, the video processing apparatus cannot correctly extract color information from the input signal and as a result incompletely displays the image.